Soil factors associated with zinc deficiency in crops and humans

Zinc deficiency is the most ubiquitous micronutrient deficiency problem in world crops. Zinc is essential for both plants and animals because it is a structural constituent and regulatory co-factor in enzymes and proteins involved in many biochemical pathways. Millions of hectares of cropland are affected by Zn deficiency and approximately one-third of the human population suffers from an inadequate intake of Zn. The main soil factors affecting the availability of Zn to plants are low total Zn contents, high pH, high calcite and organic matter contents and high concentrations of Na, Ca, Mg, bicarbonate and phosphate in the soil solution or in labile forms. Maize is the most susceptible cereal crop, but wheat grown on calcareous soils and lowland rice on flooded soils are also highly prone to Zn deficiency. Zinc fertilizers are used in the prevention of Zn deficiency and in the biofortification of cereal grains.

Zinc deficiency in selected cultivars of wheat and barley as tested in solution culture

The relative zinc (Zn) efficiencies of 33 wheat and 3 barley cultivars were determined by growing them in chelate-buffered culture solutions. Zn efficiency, determined by growth in a Zn-deficient solution relative to that in a medium containing an adequate concentration of Zn, was found to vary between 10% and 63% among the cultivars tested. Out of the 36 cultivars tested, 12 proved to be Zn efficient, 10 were Zn inefficient, and the remaining 14 varieties were classed as intermediate. The most Zn-efficient cultivars included Bakhtawar, Gatcher S61, Wilgoyne, and Madrigal, and the most Zn inefficient included Durati, Songlen, Excalibur, and Chakwal-86. Zn-efficient cultivars accumulated greater amounts of Zn in their shoots than inefficient cultivars, but the correlation between shoot Zn and shoot dry matter production was poor. All the cultivars accumulated higher concentrations of iron (Fe), copper (Cu), manganese (Mn), and phosphorus (P) at deficient levels of Zn, compared with adequate Zn concentrations. The Zn-inefficient cultivars accumulated higher concentrations of these other elements compared to efficient cultivars.

Response to zinc deficiency of two rice lines with contrasting tolerance is determined by root growth maintenance and organic acid exudation rates, and not by zinc-transporter activity

Zinc (Zn)-deficient soils constrain rice (Oryza sativa) production and cause Zn malnutrition. The identification of Zn-deficiency-tolerant rice lines indicates that breeding might overcome these constraints. Here, we seek to identify processes underlying Zn-deficiency tolerance in rice at the physiological and transcriptional levels. A Zn-deficiency-tolerant line RIL46 acquires Zn more efficiently and produces more biomass than its nontolerant maternal line (IR74) at low Zn(ext) under field conditions. We tested if this was the result of increased expression of Zn(2+) transporters; increased root exudation of deoxymugineic acid (DMA) or low-molecular-weight organic acids (LMWOAs); and/or increased root production. Experiments were performed in field and controlled environment conditions. There was little genotypic variation in transcript abundance of Zn-responsive root Zn(2+)-transporters between the RIL46 and IR74. However, root exudation of DMA and LMWOA was greater in RIL46, coinciding with increased root expression of putative ligand-efflux genes. Adventitious root production was maintained in RIL46 at low Zn(ext), correlating with altered expression of root-specific auxin-responsive genes. Zinc-deficiency tolerance in RIL46 is most likely the result of maintenance of root growth, increased efflux of Zn ligands, and increased uptake of Zn-ligand complexes at low Zn(ext); these traits are potential breeding targets.

Effects of Cigarette Smoke and Ethanol Intake on Mouse Oesophageal Mucosa Changes Induced by Dietary Zinc Deficiency and Deoxycholic Acid Supplementation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evidence of zinc deficiency in competitive swimmers

Objective: The aim of this study was to assess the nutritional zinc (Zn) status of elite swimmers during different training periods.Methods: A longitudinal paired study was performed at the University of São Paulo in eight male swimmers 18 to 25 y old who had been swimming competitively at the state and national levels for at least 5 y. The swimmers were evaluated over a total period of 14 wk: before the basic and specific preparatory period (BSPP-baseline), at the end of the basic and specific preparatory period (post-BSPP), and at the end of the polishing period (PP). Levels of Zn were determined in the plasma, erythrocyte, urine, and saliva by atomic absorption spectrophotometry. Anthropometric measurements and a 3-d food record were also evaluated.Results: The median plasma Zn concentration was below the reference value in all training periods (BSPP-baseline 59 mu g/dL, post-BSPP 55.9 mu g/dL, after PP 58.8 mu g/dL, P > 0.05), as were threshold values for erythrocytes (BSPP-baseline 36.5 mu g of Zn/g of hemoglobin, post-BSPP 42 mu g of Zn/g of hemoglobin, after PP 40.7 mu g of Zn/g of hemoglobin, P > 0.05), urinary Zn (BSPP-baseline 280 mu g/24 h, post-BSPP 337 mu g/24 h, after PP 284 mu g/24 h, P > 0.05), and salivary Zn (BSPP-baseline 66.1 mu g/L, post-BSPP 54.1 mu g/L, after PP 79.7 mu g/L, > 0.05). Salivary Zn did not correlate with plasma and erythrocyte Zn levels.Conclusion: The results suggest that the elite swimmers studied presented a possible Zn deficiency and that salivary Zn was not adequate to evaluate the Zn nutritional status. (C) 2012 Elsevier B.V. All rights reserved.

Acrodermatitis due to zinc deficiency after combined vertical gastroplasty with jejunoileal bypass: case report

CONTEXT: Nutritional complications may occur after bariatric surgery, due to restriction of food intake and impaired digestion or absorption of nutrients. CASE REPORT: After undergoing vertical gastroplasty and jejunoileal bypass, a female patient presented marked weight loss and protein deficiency. Seven months after the bariatric surgery, she presented dermatological features compatible with acrodermatitis enteropathica, as seen from the plasma zinc levels, which were below the reference values (34.4 mg%). The skin lesions improved significantly after 1,000 mg/day of zinc sulfate supplementation for one week. CONCLUSIONS: The patient's evolution shows that the multidisciplinary team involved in surgical treatment of obesity should take nutritional deficiencies into consideration in the differential diagnosis of skin diseases, in order to institute early treatment.

Evidence of zinc deficiency in competitive swimmers

Objective: The aim of this study was to assess the nutritional zinc (Zn) status of elite swimmers during different training periods. Methods: A longitudinal paired study was performed at the University of Sao Paulo in eight male swimmers 18 to 25 y old who had been swimming competitively at the state and national levels for at least 5 y. The swimmers were evaluated over a total period of 14 wk: before the basic and specific preparatory period (BSPP-baseline), at the end of the basic and specific preparatory period (post-BSPP), and at the end of the polishing period (PP). Levels of Zn were determined in the plasma, erythrocyte, urine, and saliva by atomic absorption spectrophotometry. Anthropometric measurements and a 3-d food record were also evaluated. Results: The median plasma Zn concentration was below the reference value in all training periods (BSPP-baseline 59 mu g/dL, post-BSPP 55.9 mu g/dL, after PP 58.8 mu g/dL, P > 0.05), as were threshold values for erythrocytes (BSPP-baseline 36.5 mu g of Zn/g of hemoglobin, post-BSPP 42 mu g of Zn/g of hemoglobin, after PP 40.7 mu g of Zn/g of hemoglobin, P > 0.05), urinary Zn (BSPP-baseline 280 mu g/24 h, post-BSPP 337 mu g/24 h, after PP 284 mu g/24 h, P > 0.05), and salivary Zn (BSPP-baseline 66.1 mu g/L, post-BSPP 54.1 mu g/L, after PP 79.7 mu g/L, > 0.05). Salivary Zn did not correlate with plasma and erythrocyte Zn levels. Conclusion: The results suggest that the elite swimmers studied presented a possible Zn deficiency and that salivary Zn was not adequate to evaluate the Zn nutritional status. (C) 2012 Elsevier Inc. All rights reserved.

[Acrodermatitis enteropathica-like skin lesions due to Crohn's disease-associated zinc deficiency]

We report a case of acrodermatitis enteropathica-like skin eruptions presenting with alopecia, perlèche, glossitis, and genital erosions as well as multifocal eczematoid, psoriasiform, and bullous skin lesions due to zinc deficiency in Crohn's disease.

Transient Neonatal Zinc Deficiency Caused by a Heterozygous G87R Mutation in the Zinc Transporter ZnT-2 (SLC30A2) Gene in the Mother Highlighting the Importance of Zn (2+) for Normal Growth and Development

Suboptimal dietary zinc (Zn(2+)) intake is increasingly appreciated as an important public health issue. Zn(2+) is an essential mineral, and infants are particularly vulnerable to Zn(2+) deficiency, as they require large amounts of Zn(2+) for their normal growth and development. Although term infants are born with an important hepatic Zn(2+) storage, adequate Zn(2+) nutrition of infants mostly depends on breast milk or formula feeding, which contains an adequate amount of Zn(2+) to meet the infants' requirements. An exclusively breast-fed 6 months old infant suffering from Zn(2+) deficiency caused by an autosomal dominant negative G87R mutation in the Slc30a2 gene (encoding for the zinc transporter 2 (ZnT-2)) in the mother is reported. More than 20 zinc transporters characterized up to date, classified into two families (Slc30a/ZnT and Slc39a/Zip), reflect the complexity and importance of maintaining cellular Zn(2+) homeostasis and dynamics. The role of ZnTs is to reduce intracellular Zn(2+) by transporting it from the cytoplasm into various intracellular organelles and by moving Zn(2+) into extracellular space. Zips increase intracellular Zn(2+) by transporting it in the opposite direction. Thus the coordinated action of both is essential for the maintenance of Zn(2+) homeostasis in the cytoplasm, and accumulating evidence suggests that this is also true for the secretory pathway of growth hormone.

Identification of a family of zinc transporter genes from Arabidopsis that respond to zinc deficiency

Millions of people worldwide suffer from nutritional imbalances of essential metals like zinc. These same metals, along with pollutants like cadmium and lead, contaminate soils at many sites around the world. In addition to posing a threat to human health, these metals can poison plants, livestock, and wildlife. Deciphering how metals are absorbed, transported, and incorporated as protein cofactors may help solve both of these problems. For example, edible plants could be engineered to serve as better dietary sources of metal nutrients, and other plant species could be tailored to remove metal ions from contaminated soils. We report here the cloning of the first zinc transporter genes from plants, the ZIP1, ZIP2, and ZIP3 genes of Arabidopsis thaliana. Expression in yeast of these closely related genes confers zinc uptake activities. In the plant, ZIP1 and ZIP3 are expressed in roots in response to zinc deficiency, suggesting that they transport zinc from the soil into the plant. Although expression of ZIP2 has not been detected, a fourth related Arabidopsis gene identified by genome sequencing, ZIP4, is induced in both shoots and roots of zinc-limited plants. Thus, ZIP4 may transport zinc intracellularly or between plant tissues. These ZIP proteins define a family of metal ion transporters that are found in plants, protozoa, fungi, invertebrates, and vertebrates, making it now possible to address questions of metal ion accumulation and homeostasis in diverse organisms.

Zinc deficiency induces apoptosis via mitochondrial p53- and caspase-dependent pathways in human neuronal precursor cells

Previous studies have shown that zinc deficiency leads to apoptosis of neuronal precursor cells in vivo and in vitro. In addition to the role of p53 as a nuclear transcription factor in zinc deficient cultured human neuronal precursors (NT-2), we have now identified the translocation of phosphorylated p53 to the mitochondria and p53-dependent increases in the pro-apoptotic mitochondrial protein BAX leading to a loss of mitochondrial membrane potential as demonstrated by a 25% decrease in JC-1 red:green fluorescence ratio. Disruption of mitochondrial membrane integrity was accompanied by efflux of the apoptosis inducing factor (AIF) from the mitochondria and translocation to the nucleus with a significant increase in reactive oxygen species (ROS) after 24 h of zinc deficiency. Measurement of caspase cleavage, mRNA, and treatment with caspase inhibitors revealed the involvement of caspases 2, 3, 6, and 7 in zinc deficiency-mediated apoptosis. Down-stream targets of caspase activation, including the nuclear structure protein lamin and polyADP ribose polymerase (PARP), which participates in DNA repair, were also cleaved. Transfection with a dominant-negative p53 construct and use of the p53 inhibitor, pifithrin- ␮, established that these alterations were largely dependent on p53. Together these data identify a cascade of events involving mitochondrial p53 as well as p53-dependent caspase-mediated mechanisms leading to apoptosis during zinc deficiency.

Analysis of plasma and erythrocyte zinc levels in premenopausal women with breast cancer

Introduction: Zinc deficiency has been associated with damage and oxidative changes in DNA that may increase an individual`s risk of cancer. Furthermore, zinc metabolism may be affected in cancer patients, leading to alterations in its distribution that would favor carcinogenesis. Plasma and erythrocyte zinc levels in women with breast cancer were evaluated in this cross-sectional, controlled study. Material and methods: Fifty-five premenopausal women of 25 to 49 years of age with and without breast cancer were divided into two groups: Group A, composed of women without breast cancer (controls, n = 26) and Group B, composed of women with breast cancer (cases, n = 29). Plasma and erythrocyte zinc levels were measured by flame atomic absorption spectrophotometry at gamma = 213.9 nm. Diet was assessed using the 3-day diet recall method and analyzed using the NutWin software program, version 1.5. Student`s t-test was used to compare means and significance was established at p <0.05. Results: Mean plasma zinc levels were 69.69 +/- 9.00 g/dt, in the breast cancer patients and 65.93 +/- 12.44 g/dt. in the controls (p = 0.201). Mean erythrocyte zinc level was 41.86 +/- 8.28 mu gZn/gHb in the cases and 47.93 +/- 7.00 mu gZn/gHb in the controls (p < 0.05). In both groups, dietary zinc levels were above the estimated average requirement. Conclusions: The present results suggest that zinc levels are lower in the erythrocyte compartment of premenopausal women with breast cancer.

Rhizosphere properties of rice genotypes as influenced by anoxia and availability of zinc and iron

The objective of this work was to study possible mechanisms involved in root-induced changes of rhizosphere physicochemical properties of rice genotypes, under anoxia and low supply of Zn and Fe. Two rice genotypes, including an upland and a lowland ones, were grown in hydroponic medium under adequate and low supply of Zn and Fe, with or without aeration. Anoxia increased shoot dry weight, root length and uptake of Zn and Fe in lowland Amol genotype, but reduced these parameters in upland Gasrol-Dashti genotype. The amount of oxygen released by roots was statistically higher in 'Amol'. The highest acidification potential of roots was observed in the lowland genotype under low supply of Zn, and in the upland genotype under Fe starvation. The highest oxalate (only organic acid detected) exudation from roots was observed in Zn and Fe deficient Gasrol-Dashti genotype. Zinc deficiency caused reduction of alcohol dehydrogenase and stimulation of lactate dehydrogenase activity, particularly in shoot. The ability to induce changes in the rhizosphere properties has a great contribution for the adaptation of both lowland and upland rice genotypes to specific soil conditions.

Factores asociados a deficiencia de zinc en niños colombianos entre 1 y 4 años de edad

Introducción: Las deficiencias de micronutrientes continúan siendo un problema de salud pública en la población infantil, dentro de las ellas se ha encontrado a la deficiencia de zinc causa importante de morbi-mortalidad en los países en desarrollo, la nutrición adecuada de zinc es esencial para un crecimiento adecuado, inmunocompetencia y desarrollo neuroconductual; se dispone de información insuficiente sobre el estado de zinc en la población preescolar lo cual dificulta la expansión de las intervenciones para el control de su deficiencia. Colombia presenta una deficiencia de este micronutriente, considerándose a nivel mundial como un problema de salud pública moderado a severo. Una evaluación sobre la prevalencia y factores determinantes asociados puede proporcionar datos sobre el riesgo de deficiencia de zinc en una población, considerando factores demográficos, sociales y nutricionales que podrían predisponer a la población preescolar colombiana a sufrir este déficit. Metodología: Estudio observacional de corte transversal que incluyó 4275 niños entre 1 y 4 años, utilizando datos de la Encuesta Nacional de Situación Nutricional (ENSIN-2010). Se realizaron análisis bivariados y multivariados para determinar factores asociados positiva y negativamente con deficiencia de zinc. Resultados: El 49,1% de los niños encuestados cursaban con deficiencia de zinc. Los factores de riesgo asociados a deficiencia de zinc encontrados fueron menor edad, peso y talla bajos, vivir en región Atlántica, región Central, Territorios Nacionales, vivienda en área de población dispersa, pertenencia a etnia afrocolombiana, pertenencia a etnia indígena, estar afiliado a régimen subsidiado, no estar afiliado a ningún régimen de salud, madre sin educación, no asistencia a programa de alimentación dirigido y el grado severo de inseguridad Conclusiones: El déficit de zinc en los niños entre 1 y 4 años de edad es multifactorial, siendo un reflejo probable de la situación de inequidad de la población colombiana, en especial, la más pobre y vulnerable. Palabras clave: Zinc, Deficiencia de zinc, factores asociados, niños entre 1 y 4 años, Colombia